One of my drawings keeps crashing when I delete a layer, but it doesn't do it every time... However this particular file has crashed this way a few times after deleting layers. It was doing this under DataCAD 18, hoped it was an unmentioned fix in 19, no luck though. Generally, they are packed layers 1000+ entities, deleting via the always on Layer Manager. It has not happened through the utility menu. The crash doesn't affect the program or any other open drawings thankfully.

Going to purge my file and hope that clears what ever the issue is, just wanted to share what I have been running into, and recommend you save before deleting layers (just like I save before editing any hatched poly lines - old habit that I picked up way back from the datacad 12 days LOL)

Not 100% sure what is going on but one thing to try is copy all of the contents of the layer(s) in question to the clipboard. Close and purge the file and when purging make sure to uncheck the layer(s) you copied in the previous step. Once the file is purged, open it and then paste the clipboard entities using Original Layer and Absolute Zero to have Datacad create a new layer named with the old layers name and put the entities back on the new fresh layer.

The majority of the symbols appear to be left overs from previous projects - base plans that have been pulled forward through a few different projects, sheets bound then the layer deleted, but the symbols remained. One of our basic office drawing note symbols even refers back to my DataCAD 12 symbol folder. (Yeah, I am one of those people that still has every DataCAD installation still on my PC).

None appear to be DataCAD's built in symbols though, to answer your question Dave.